FR3054603A1 - METHOD FOR CORRECTING THE MEASUREMENT OF A FLOWMETER IN AN INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

The invention relates to a method for correcting the measurement of a flow rate of fresh air introduced into a direct injection internal combustion engine comprising at least one cylinder equipped with a pressure sensor, a gas recirculation circuit. exhaust and a measuring member of a fresh air flow introduced into the engine, comprising the following steps: • from measurements of pressure in the cylinder by the sensor and fresh air flow introduced into the engine by the measuring device in at least one phase during which no exhaust gas recirculation takes place in the engine, determining (100) an error of the measuring device on a measured flow value fresh air introduced into the engine, and • from the determined error (110), generation (200) of a corrected value of the fresh air flow introduced into the motor measured by the measuring member.

Description

Holder (s): CONTINENTAL AUTOMOTIVE FRANCE Simplified joint-stock company, CONTINENTAL AUTOMOTIVE GMBH.

Extension request (s)

Agent (s): CONTINENTAL AUTOMOTIVE FRANCE Simplified joint-stock company.

FR 3 054 603 - A1 (54) METHOD FOR CORRECTING THE MEASUREMENT OF A FLOW METER IN A COMBUSTION ENGINE

INTERNAL.

(57) The invention relates to a method for correcting the measurement of a flow rate of fresh air introduced into an internal combustion engine with direct injection comprising at least one cylinder fitted with a pressure sensor, a recirculation circuit of exhaust gas and a device for measuring a flow of fresh air introduced into the engine, comprising the following steps:

from measurements of pressure in the cylinder by the sensor and flow rate of fresh air introduced into the engine by the measuring device during at least one phase during which no exhaust gas recirculation has place in the engine, determination (100) of an error of the measuring device on a measured value of flow rate of fresh air introduced into the engine, and from the determined error (110), generation (200) of a corrected value of the fresh air flow introduced into the engine measured by the measuring device.

The invention relates to a method for correcting the measurement of a flow rate of fresh air introduced into an internal combustion engine, and a device for carrying out said correction.

The invention applies to direct injection engines, which may be of the Diesel type or direct injection petrol engines.

A diesel type engine conventionally comprises a cylinder in which a movable piston makes it possible to compress air. Fuel is then injected under pressure into the cylinder. The combustion of fuel with compressed air results from the pressure and temperature conditions in the cylinder.

The combustion of fuel at high temperature generates the production of polluting gases, and in particular of nitrogen oxides called NO _X such as nitrogen monoxide NO, nitrogen dioxide NO ₂ , etc.

Engines have been developed which include an exhaust gas or flue gas recirculation circuit also known by the acronym EGR (for "Exhaust Gas Recirculation"). Such a circuit takes part of the exhaust gases resulting from combustion and reinjects them, by mixing them with fresh air, into the cylinder during subsequent combustion.

In doing so, it is possible to reduce the combustion temperature of the air-fuel mixture and to reduce the amount of nitrogen oxides generated.

With this type of engine, car manufacturers are now imposing nominal values on the amount of nitrogen oxides generated by the combustion of fuel. However, compliance with these constraints can be obtained by controlling and controlling the flow of recirculated exhaust gas.

The Applicant has filed patent application WO 2014/095052 in which there is proposed a method for determining the flow rate of recirculated exhaust gas in an internal combustion engine, from an air pressure measured in the cylinder and the fresh air flow introduced into the engine, measured by a dedicated flow meter.

By virtue of this process, the value of the flow rate of exhaust gas recirculated in the engine therefore depends on the measured value of the flow rate of fresh air introduced into the engine.

However, the flow meters used to measure the flow of fresh air introduced into the engine have a margin of error which induces a significant variation in the quantity of nitrogen oxides generated by combustion. This variation is illustrated in FIG. 1a, which represents the variation of the emissions of nitrogen oxides and of particles as a function of the error on the measurement of the flow meter.

In particular, it is noted that a margin of error of the order of plus or minus 6% on the value of the fresh air flow rate measured by the flow meter can result in a variation in the quantity of nitrogen oxides emitted. by the vehicle which can reach 133 mg / km, on a target value of the order of 200 mg / km.

In order to significantly reduce the quantities of nitrogen oxides generated during the combustion of the engine, it is therefore necessary to reduce the margin of error of the flow meter measuring the amount of fresh air introduced into the engine.

In view of the above, the invention aims to provide better control of the flow rate of recirculated exhaust gas in an internal combustion engine with direct injection.

In particular, an object of the invention is to propose a means of reducing the margin of error of a flow meter measuring a flow rate of fresh air introduced into the engine.

Another object of the invention is to propose a method for correcting the error of such a flow meter.

Another object of the invention is to be applicable to diesel or petrol type direct combustion engines.

In this regard, the subject of the invention is a method for correcting the measurement of a flow rate of fresh air introduced into an internal combustion engine with direct injection comprising at least one cylinder fitted with a pressure sensor, a circuit for exhaust gas recirculation and a device for measuring a flow of fresh air introduced into the engine, characterized in that it comprises the following steps:

• from cylinder pressure measurements by the pressure sensor and from the fresh air flow introduced into the engine by the measuring device during at least one phase during which no exhaust gas recirculation does not take place in the engine, determination of an error of the measuring device on a measured value of flow rate of fresh air introduced into the engine, and • from the determined error, generation of a corrected value of the fresh air flow introduced into the engine measured by the measuring member.

Advantageously, but optionally, the method according to the invention can also comprise at least one of the following characteristics:

• the step of determining a measurement organ error can include:

- during a plurality of phases during which no exhaust gas recirculation takes place, the calculation of an error value of the measuring device on the measured value of fresh air flow, and

- establishing, from the calculated error values, a relationship between the error of the measurement device and the measured flow value,

- and the step of generating a corrected value is then implemented from the relationship between the error of the measurement device and the measured flow value.

• establishing a relationship between the error of the measuring device and the flow rate value measured from the calculated error values can be implemented by linear regression.

• the method being implemented in an engine in which the exhaust gas recirculation circuit comprises at least one controllable valve for selectively opening or closing the circuit, in order to respectively authorize or block an exhaust gas recirculation, the calculation of error values of the measurement device is then implemented during at least one phase among:

- an engine deceleration phase, during which each valve is controlled to close the exhaust gas recirculation circuit, or

- a phase during which each valve is closed, corresponding to a phase during which the engine torque is between 90 and 100% of the maximum engine torque.

The calculation of error values of the measuring device can be implemented during at least one engine deceleration phase during which each valve is controlled to close the exhaust gas recirculation circuit, and at least one phase during which each valve is closed and the engine torque is between 90 and 100% of the maximum engine torque.

The method can also comprise the measurement of the time gradient of the fresh air flow measured by the measuring member, and in which the error value is calculated only if the time gradient of the fresh air flow measured by the measuring device is below a determined threshold.

• an error value can be obtained during a phase during which no exhaust gas recirculation takes place by:

- the simultaneous measurement, during a combustion cycle, of a value of flow rate of fresh air introduced into the engine by the measuring member and of a value of the total flow rate of air circulating in the engine established at from the pressure measured in the cylinder, and

- the subtraction, from the value of total air flow circulating in the engine, of the value of fresh air flow measured.

• the step of generating the corrected value of the air flow can be implemented by subtracting, from the measured value of the fresh air flow introduced into the engine, the determined error.

• the fresh air flow value measured by the measuring device can be filtered using a low-pass filter.

According to a second object, the invention also relates to a computer program product, comprising code instructions for implementing the steps consisting in:

• from a pressure value in a cylinder of an internal combustion engine comprising an exhaust gas recirculation circuit, and from a value of fresh air flow introduced into the engine measured simultaneously during a phase during which no exhaust gas recirculation takes place in the engine, calculate an error on the measured fresh air flow value, and • correct the measured fresh air flow value from the calculated error value, when implemented by a processor.

According to a third object, the invention also relates to a device for correcting the measurement of a flow rate of fresh air introduced into an internal combustion engine comprising at least one cylinder equipped with a pressure sensor, a recirculation circuit of exhaust gas and a device for measuring a fresh air flow rate introduced into the engine, the correction device comprising a controller in communication with the pressure sensor and the measurement device, characterized in that the controller is suitable for implementing the method according to the above description.

Finally, the invention also relates to an internal combustion engine, comprising at least one cylinder equipped with a pressure sensor, an exhaust gas recirculation circuit, a member for measuring a flow of fresh air. introduced into the engine, and a correction device as described above.

The proposed method makes it possible to correct the measurement of a flow meter measuring a flow rate of fresh air introduced into the engine, by basing the correction on a more precise measurement which is obtained by the pressure in the cylinder.

In fact, the margin of error on the fresh air flow introduced into the engine goes from plus or minus 6% to plus or minus 2.5%, which significantly reduces the margin of error on nitrogen oxides generated by combustion.

In addition, reducing the margin of error on the quantities of nitrogen oxides produced also makes it possible to reduce the production of carbon dioxide from the engine. This is illustrated schematically in Figure 1b, which illustrates that the production of carbon dioxide is inversely proportional to the production of nitrogen oxides.

To guarantee compliance with a nominal nitrogen oxide emission value prescribed by a manufacturer, it is necessary to take into account the margin of error on the flow meter. By reducing this margin of error we get closer to the expected nominal value and we can therefore reduce CO ₂ emissions. For example, by reducing the margin of error on the measurement of the flowmeter by 10 mg / km of NO _X emission, one can reduce CO ₂ emissions by 1 g / km.

In addition, the method provides for determining the error on the measurement of the flow meter both during phases of deceleration of the engine, and during phases where the engine torque is high and where there is no recirculation of gas. exhaust. These two types of phases correspond to very different levels of flow rates of fresh air introduced into the engine, which improves the accuracy in calculating the error of the flow meter, and therefore provides better correction to the flowmeter measurement.

Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows, with regard to the appended figures, given by way of non-limiting examples and in which:

FIG. 1a, already described, represents the impact of the error of the flow meter measuring the flow of fresh air introduced into the engine on the emission of nitrogen oxides and of particles produced by combustion,

- Figure 1b, already described also, shows the effect of reducing the error of the flow meter on the calibration margins of nitrogen oxide emissions and on CO ₂ emissions.

FIG. 2a schematically represents an internal combustion engine in which a method for correcting the measurement of a flow meter can be implemented,

- Figure 2b shows the pressure in the cylinder as a function of the position of the crankshaft in a direct injection engine.

- Figure 3 shows schematically the main steps of a method for correcting the measurement of a flow meter.

- Figure 4 is a graph simultaneously combining the vehicle speed, engine speed, engine torque, and the flow of fresh air introduced into the engine and measured by a flow meter as a function of time.

- Figure 5 shows a flow diagram of an example of implementation of the method according to an embodiment of the invention.

Architecture of the internal combustion engine

Referring to Figure 2a, there is shown an internal combustion engine 1, which comprises at least one cylinder 10, and a pressure sensor 11, called cylinder pressure sensor, suitable for measuring the pressure in the at least one cylinder 10.

The internal combustion engine also includes an exhaust gas recirculation circuit 20, which makes it possible to take part of the products of the combustion of fuel in the cylinder, and to make it recirculate in order to redirect it towards the cylinder during a subsequent combustion. The exhaust gas recirculation circuit 20 can conventionally comprise a high pressure recirculation branch 21, near the gas outlet of the cylinder, and a low pressure recirculation branch 22, further downstream of the cylinder, and where the gases circulating have been relaxed.

In addition, the exhaust gas recirculation circuit 20 comprises at least one valve 23 which can be controlled to open and close, the valve being adapted to respectively authorize, prohibit, or regulate the circulation of exhaust gases in the circuit. 20. Advantageously, in the case where the recirculation circuit 20 comprises a high pressure branch 21 and a low pressure branch 22, it also includes a valve 23 in each branch, each making it possible to selectively authorize, prohibit or regulate the circulation of gases in the corresponding branch.

The engine 1 also includes a fresh air inlet duct 30 to be introduced into the cylinder, and a device for measuring the fresh air flow rate 31 introduced, for example a flow meter.

The fresh air inlet pipe 30 as the exhaust gas recirculation circuit 20 open into the cylinder 10 so as to introduce into the cylinder a mixture of fresh air and recycled exhaust gases in adjustable proportions.

Engine 1 is a direct injection engine, that is to say that it comprises one or more fuel injectors (not shown) which opens (s) directly into the combustion chamber of the cylinder, rather than upstream of the cylinder in the air inlet duct opening into the cylinder.

Typically, the engine can be a diesel type engine.

Alternatively, with reference to FIG. 2b, the engine can be a petrol engine type with direct injection. In this case, it is preferable that the engine is designed so that there is a range of rotation of the crankshaft of at least 20 ° between the closing of the intake valve and the initiation of combustion during which no injection of fuel does not take place. This represents a period during which the composition of the content of the cylinder chamber does not vary and makes it possible to implement the correction method described below.

Returning to FIG. 2a, the motor 1 also comprises a device 40 for correcting the measurement of the fresh air flow rate of the flow meter 31. This device 40 comprises a controller 41, for example a microcontroller, which includes communication interfaces dedicated 42 allowing it to communicate with the flow meter 31 and the pressure sensor 11 of the cylinder in order to receive from them the values they have measured. The controller also includes a communication interface 43 with the valve or valves 23 of the recirculation circuit 20 in order to control in particular the opening and closing of the valves.

Finally, the controller 41 includes a memory 44 and processing means, for example a processor 45, adapted to implement the method for correcting the measurement of the flowmeter described below.

Method for correcting the measurement of the flow meter

Referring to Figure 3, the correction device 40 implements a method for correcting the measurement of the flow rate of fresh air introduced into the engine and measured by the flow meter 31.

This method comprises a first step 100 of determining an error of the flow meter 31 on the measurement that it performs.

This step 100 includes the calculation 110 of an error value on the flow of fresh air measured by the flow meter during at least one phase during which no recirculation of exhaust gases takes place in the engine. .

This step is implemented from a simultaneous measurement:

• the flow of fresh air introduced into the engine by the flow meter 21, and • the pressure in the cylinder, by the pressure sensor 11, during a combustion cycle of the engine.

In fact, when no exhaust gas recirculation takes place, the flow of recirculated exhaust gas is zero. This therefore implies that the only gas that is used for combustion is the fresh air introduced into the engine, the flow rate of which is measured by the flow meter.

It is then possible, during periods of air compression in the cylinder during the combustion cycle, and before fuel is injected into the cylinder, to determine from the pressure measured in the cylinder by the sensor. pressure 11, the mass of fresh air introduced into the engine during a combustion cycle, and to deduce the flow of fresh air introduced into the engine during this cycle. In the absence of exhaust gas recirculation, this fresh air flow must be equal to that which was measured by the flow meter, and which is measured simultaneously.

However, as the flow meter is located upstream of the cylinder 10 relative to the fresh air circuit in the engine, the data measured by the flow meter is advantageously filtered by a low-pass filter, so as to introduce a delay in the measurement. of the flow meter which brings the measured value of the flow of fresh air actually simultaneous to the value calculated from the pressure in the cylinder, and therefore makes the comparison between the two flow values more relevant. This filter is advantageously applied by the controller 41.

The determination of the fresh air flow rate from the cylinder pressure is implemented by applying the method described in application WO 2014/095052, to which reference may be made for more details of implementation. In particular, the method described there is applied in the case where the mass of recycled exhaust gas is zero.

In summary, to determine the mass of gas in each cylinder of the engine from the pressure in the corresponding cylinder, the following formula is applied:

MY F,

CYL

Γ dV al] ί ^c ^ ^X ci (crfc) ^X CV J dTçyl d (crk)

Or :

• MAFcyl is the mass of gas in the cylinder considered, • P _cy i is the pressure measured in the cylinder, • dV / d (crk) is the change in volume in the cylinder for an angular change in the crankshaft equal to d (crk ), • dT _cy i / d (crk) is the temperature variation in the cylinder for an angular variation of the crankshaft equal to d (crk), • CV is the heat capacity at constant volume of the mass of gas, and • a -1 is a corrective term representing consideration of thermal losses.

Then we determine the mass of gas in all the engine cylinders over a complete combustion cycle, and we deduct by equality the mass of fresh air corresponding to the same complete combustion cycle. Knowing the geometry of the fresh air inlet duct 30 and the duration of the combustion cycle (or the speed of rotation of the engine), the flow of fresh air introduced into the engine during the combustion cycle is deduced therefrom.

Since the fresh air flow calculated from the cylinder pressure measurement must be equal to that measured by the flow meter, in the absence of exhaust gas recirculation, the error value is calculated during step 110 as the difference between the flow rate measured by the flow meter and the flow rate calculated from the cylinder pressure, because indeed the precision on the flow rate calculated from the cylinder pressure is greater than the accuracy of the flow meter.

Step 110 makes it possible to obtain an error value; however, for better accuracy of the error value, the method advantageously comprises the calculation of several error values, each time during phases without exhaust gas recirculation.

Referring to Figure 4, we will now describe the phases during which no exhaust gas recirculation takes place. These phases correspond to periods when the valves 23 for closing the circulation in the recirculation duct are closed. Two types of phases can be used to calculate an error value.

First, the valves 23 are conventionally closed when the engine torque is high, and a flow of fresh air introduced into the engine is very important to support high engine performance. Typically, the engine torque is comprised during these phases P1 between 90 and 100% of the maximum engine torque that the engine can deliver. During these phases, no exhaust gas recirculation takes place, to promote the combustion of fresh air and optimize engine performance.

A second type of phase P2 comprising no recirculation of exhaust gas, is a phase of deceleration of the engine, because during these phases no combustion takes place. In this case, the method comprises a control, by the controller, of the valves 23 to close them, in order to guarantee the total absence of circulation of exhaust gases and therefore the equality between the flow of fresh air calculated from of the cylinder pressure measurement, and the fresh air flow measured by the flow meter.

As can be seen in FIG. 4, the phases P1 and P2 correspond to different ranges of flow rates of fresh air introduced into the engine: the phases P1 are phases of high flow rate of fresh air, and the phases P2 are phases of relatively lower air flow.

However, the error of the flow meter is variable depending on the flow it measures. Consequently, it is preferable to carry out at least one error calculation during each phase, in order to obtain at least one error value corresponding to a range of low air flow and at least one error value corresponding to a range of high air flow. This increases the accuracy of the overall error determined from the measured error values.

In addition, in order to improve the reproducibility of the measurements and the accuracy of the calculated error value, the calculation step 110 is preferably only implemented when the time gradient of the air flow measured by the flow meter is below a certain threshold. To do this, the time derivative of the air flow measured by the flow meter is continuously monitored, and step 110 is only authorized by the controller when it is below the said threshold.

Following the step 110 of calculating at least one error value in one and / or the other of the phases P1 and P2, the method comprises a step 120 of establishing, from the error values readings for a set of values of air flows measured by the flow meter, of a relation between the error of the flow meter and the measured fresh air flow.

This step is preferably implemented by linear regression.

Once the error has been determined as a function of the fresh air flow rate measured by the flow meter, the method comprises a step 200 of generating corrected values of the fresh air flow rate measured by the flow meter, by subtracting, from the value measured, the corresponding error value for this flow.

Referring to FIG. 5, a flow diagram shows an example of implementation of the correction method.

In a step S101, it is determined whether the valves 23 are closed and therefore prohibit the recirculation of exhaust gases in the engine. If yes, the method continues to step S102. Otherwise it continues to step S103.

In step S103, it is determined whether the engine is in a deceleration phase. If yes, then during a step S104 the controller controls the valves 23 to close them, and the method continues to step S102. Otherwise it continues to step S106.

In step S102, the controller determines whether the time gradient - or time variation - of the air flow measured by the flow meter is less than a determined threshold. If yes, the method continues to step S105, otherwise it continues to step S106.

As a variant, this step can be a prior step taking place before step S101 and which conditions the continuation of the process towards this step. In this case, once the valves are closed, the process continues directly to step S105 described below.

In step S105, the controller simultaneously recovers:

• the value of the pressure in each cylinder, and • the flow of fresh air measured by the flow meter, advantageously filtered by the low-pass filter.

The controller calculates from these values, and as explained above, a flowmeter error value for the measured flow value, and stores this value and the associated flow in memory 44. The process then continues with the step S106.

In step S106, the controller calculates a linear regression on all of the error values recorded in memory 44 associated with the corresponding flow rate values.

The method then continues to step S107, which corresponds to the correction step 200 of the measurement of the flow meter from the error function which has been determined. The process then continues to step 101.

As in the example in FIG. 5, the correction method is preferably iterative, namely that the error obtained at the end of step 120 is recorded in memory 44, and steps 110 and 120 are repeated during subsequent phases P1 and P2 to make the error converge towards a stable value, and to keep it good accuracy over time in the event of a variation in the error of the flowmeter linked to its aging.

The updated error is then taken again in step 200 to correct the measurement of the flow meter.

A good convergence of the error is observed since it suffices to implement the calculation step 110 on a phase P1 and a phase P2 of four acceleration-deceleration sequences for the coefficient of determination R ² of the regression linear is greater than 0.8.

This results in a reduction of the margin of error on the value of the fresh air flow measured by the flow meter from 6% without the correction to around 2.5% after correction, which allows finer control of the gas flows exhaust recirculated and results in a visible reduction in the variability of nitrogen oxide emissions, as seen in Figure 1a, and in a reduction of carbon dioxide emissions.

Claims (12)

1. Method for correcting the measurement of a flow rate of fresh air introduced into an internal combustion engine with direct injection comprising at least one cylinder (10) equipped with a pressure sensor (11), a circuit (20) exhaust gas recirculation and a measuring member (31) of a flow of fresh air introduced into the engine, characterized in that it comprises the following steps: • from measurements of pressure in the cylinder (10) by the pressure sensor (11) and of the flow of fresh air introduced into the engine by the measuring member (31) during at least one phase during from which no exhaust gas recirculation takes place in the engine, determination (100) of an error of the measuring member (31) on a measured value of flow rate of fresh air introduced into the engine, and • from the determined error, generation of a corrected value (200) of the fresh air flow introduced into the engine measured by the measuring member (31). 2. A correction method according to claim 1, in which the step of determining (100) an error of the measurement device comprises: • during a plurality of phases during which no recirculation of exhaust gases takes place, the calculation (110) of an error value of the measuring member (31) on the measured value of flow fresh air, and • establishing (120), from the calculated error values, a relationship between the error of the measuring member and the measured flow value, and the generation step (200) of a corrected value is implemented from the relationship between the error of the measuring member and the measured flow value. 3. The correction method as claimed in claim 2, in which the establishment (120) of a relationship between the error of the measuring member (31) and the value of flow measured from the calculated error values is implemented by linear regression. 4. Correction method according to one of claims 2 or 3, implemented in an engine in which the exhaust gas recirculation circuit (20) comprises at least one valve (23) controllable to selectively open or close the circuit, in order to respectively authorize or block a recirculation of exhaust gases, and the calculation of error values of the measuring device is implemented during at least one phase among: • a phase (P2) of engine deceleration, during which each valve is controlled to close the exhaust gas recirculation circuit, or • a phase (P1) during which each valve is closed, corresponding to a phase at during which the engine torque is between 90 and 100% of the maximum engine torque. 5. Correction method according to claim 4, in which the calculation of error values of the measuring member is implemented during at least one deceleration phase (P2) of the engine during which each valve is controlled. to close the exhaust gas recirculation circuit, and at least one phase (P1) during which each valve is closed and the engine torque is between 90 and 100% of the maximum engine torque. 6. Correction method according to any one of claims 2 to 5, further comprising measuring (S102) the time gradient of the fresh air flow measured by the measuring member, and wherein the error value n 'is calculated only if the time gradient of the fresh air flow rate measured by the measuring device is less than a determined threshold. 7. Correction method according to any one of the preceding claims, in which an error value is obtained during a phase during which no recirculation of exhaust gases takes place by: • the simultaneous measurement, during a combustion cycle, of a value of flow rate of fresh air introduced into the engine by the measuring member (31) and of a value of the total flow rate of air circulating in the engine established from the pressure measured in the cylinder (10), and • the subtraction, from the value of total air flow circulating in the engine, from the value of measured fresh air flow. 8. Correction method according to any one of the preceding claims, in which the step of generating (200) the corrected value of the air flow is implemented by subtraction from the measured value of the fresh air flow. introduced into the engine, from the determined error. 9. Correction method according to any one of the preceding claims, in which the value of fresh air flow rate measured by the measuring member (31) is filtered by means of a low-pass filter. 10. Product computer program, including code instructions for implementing the steps of: • from a pressure value in a cylinder (10) of an internal combustion engine comprising an exhaust gas recirculation circuit (20), and from a value of fresh air flow introduced into the engine measured simultaneously during a phase during which no gas recirculation 5 there is no exhaust in the engine, calculate (110) an error on the measured fresh air flow value, and • correct (200) the fresh air flow value measured from the value d 'calculated error, when implemented by a processor (45). 10 11. Correction device (40) for measuring the flow of fresh air introduced into an internal combustion engine comprising at least one cylinder (10) equipped with a pressure sensor (11), a recirculation circuit ( 20) of exhaust gas and a member (31) for measuring a flow rate of fresh air introduced into the engine, the correction device (40) comprising a controller (41) in communication with the pressure sensor (11 ) and 15 the measuring member (31), characterized in that the controller (41) is adapted to implement the method according to any one of claims 1 to 9. 12. Internal combustion engine (1), comprising at least one cylinder (10) equipped with a pressure sensor (11), an exhaust gas recirculation circuit (20), a member (31) for measuring d '' a flow of fresh air introduced into the engine, and a device for 20 correction (40) according to the preceding claim. 1/6 Π3 Face value E X O O o (lu> I / d6) seinoibied 2/6